Vibrator



Cil

Patented Mar. i8, 1941.

PATENT' OFFICEv VIBRATOR Henry M. Dressel,v Chicago, Ill., assignor to Oak Manufacturing Company, Chicago, Ill., a corporation of Illinois Application April 29, 1939, Serial No. 270,877 14 Claims. (Cl. 20o-90) This invention relates to vibrators andparticularly to vibrators operating at frequencies high in comparison to the frequencies in use at present.

At the present time the greatest iield'for use of vibrators is in connection with the power supplies of radio receivers or transmitters, particularly for automobiles and air craft. A low voltage direct current from a suitable battery may be interrupted' by a vibrator and stepped up by means of a transformer to a satisfactory voltage level. Thereafter the alternating currents may be rectified and filtered or treated in any other desired manner. In most instances however these alternating currents are rectified and filtered, the latter being accomplished by the use of chokes and condensers. As is well known, the size,

weight and cost of the transformers and filtering equipment is substantially reduced with increase in frequency of interrupted current. Hence, an increase in the cost of the vibrator itself may be tolerated if the resulting frequency is suiciently high so that the overall cost of the entire system is reduced.

This invention attains the object of higher operating frequencies in a manner diierent than heretofore used. lThe invention utilizes arelatively weak spring and high loading at the contacts. The energy is fed into a. part having substantially small amplitude. In fact this Dartthe armature-is connected to the movable contact by a rigid member so that, to use an electrical analogy, the coupling is almost perfect. However, to store energy in the vibrating part of the system, a separate spring and weight are used which only comes into play after theV device has started In fact,the reduced armature amplitude and its substantially constant range permit a closer dis- The vibrator of the present invention is of the vshunt coil type wherein each magnetizing coil is alternately shunted out. In combination with a 'center-tapped transformer primary it is particularly desirable and effective. The present-day type of vibrator having a single driving shunt -and transformer has what might be termed a neutral electrical axis with everything symmetrical around it.

Referring to the drawings: p

Figure l is an elevation partly in section of a vibrator;

Fig. 2 is a sectional view along line 2-2 of Fig. 1; A

Fig. 3 is a detail of the vibrator frame;

Fig. 4 is a detail of the vibrating element of the vibrator;

Fig. 5 is an exploded View of the' vibrator and its -parts' with certain portions broken away; and

Fig. 6 is a circuit diagram of the vibrator.

The frame of the Vibrator may take on a variety of forms but is preferably made in the form shown in Fig. 3 for the reason that the frame may be made out of one piece in a simple stamping operation. The frame has a generally U- shape and comprises a bottom portion IIJ with a pair of upstanding sides II and I2. Sides II and I2 may be provided with windows I3 and I4 and terminate in reduced extensions I5 and I6 opposing each other.

Extension I5 has a pair of iingers II and I8 integral therewith and bent at right angles to the plane of side II. It will be noted that while vfingers I'I and I8 lie in parallel planes they are offset from each other. Similarly extension I6 is provided with offset fingers I 9 and 20 generally similar to fingers I'I and I8 to form two pairsof fingers I1 and I9, and I8 and V20. These various fingers are provided with apertures 2l to 24 inclusive.

Bottom portion I0 has a tongue 25 cut out therefrom and extending upwardly perpendicular to and between sides II' and I2 to form a magnetic polepiece. Opposing arms II and I9 have adjustably bolted thereto at apertures 2l and 23 a generally Z-shaped member 28 made up of pole piece portion 29, and portionsll and 3|.

vMounting portion 3l is wide enough to overlie both lingers Il and i9. This Z-Shape member 23 5 is rigidly maintained in predetermined position upon ngers I'l and i9 and by bolts 33. The pole face of portion 29 of Z-sha'pe member 26 is preferably of the same dimensions as the pole face of pole piece 25. Pole pieces 25 and 29 have disposed over them magnetizing windings 35 and 36 respectively.

. Fingers i8 and 2@ are adapted -to support the stationary contacts and movable portion of the system. Fig. 4 shows the entire movable portion of the system and will now be described in detail, A pair of short spring members 39 and 39 operating as a unit are provided-with apertures All) and 9i at one end of each of said springs, this end being the rigidly clamped portion of the spring. The other end of each of springs 38 and 39 are riveted at 52 and i3 at a rigid beam member generally designated by numeral 95.

This beam member l5 consists of a pair of side arms 96 and il extending downwardly from4 springs 38 and 39 and having an armature 99 connecting the free ends thereof. The top portions of side arms 96 and ll have spring supporting portions 59 and 5l at which point the rivets 92 and 93 are located. These spring supporting portions 59 and 5l extend toward each other and merge into a central beam portion 52 which may be curved or dished for strength, Beam portion 52 extends upwardly away from armature i9 and beyond the rigidly clamped end of springs 39 and 39. Beam portion 5l may be shaped in any suitable fashion and preferably tapers to a contact supporting portion 59 carrying contacts 55 and 56 on opposite sides thereof.

So far the mass of the beam as a Whole is concentrated above the light frame of which the armature forms a part. In order to stabilize the operation of the vibratory system and to'control the dwell of the movable contact against the stationary contacts a supplementary spring system ,3 is provided. At 5l -the beam spreads sideways and has attached thereto springs 59 and 59 extending beyond the movable contacts 55 and 55. A weight 60 is carried by the top ends of springs 59 and 59.

Normally the entire vibrating element is not stily mounted if the stationary contacts are not considered. It is clear that unless the stationary contacts are hit, the resonant frequency of the beam structure is substantially due to supporting springs 38 and 39. This may be of the order of 50 to 100 cycles per second in a vibrator for commercial use in an-automobile radio. The springs 58 and 59 are considerably stiffer than 33 and 39 and at frequencies of 50 or 100 cycles per second 60 may be considered as rigid members. It is only at higher frequencies that the energy stored in weight 6U is sufcient to utilize the resilience of springs 58 and 59 and control the dwell of the contacts. Under certain conditions, springs 58 and^59 may be prolongations of the beam proper. The entire vibrating structure is clamped to the frame by suitable bolts 6I passing through apertures 22 and 2li of fingers I9 and 26 through apertures 9| and l0 of the vibrating portion of the system. It will be noted that springs 33 and 0 39 are disposed directly against the faces of iingers I8 and 2 respectively and thus are in good magnetic and electrical contact therewith. Disposed around bolts 6| are insulating sleeves 63 and 64 on opposite sides of the spring and nger metal portion.

A pair of stationary contact support members 65 and 66 are disposed on bolts 6l beyond insulating sleeves 63 and 69. These stationary contact members are similar and as shown in Fig. 5 comprise, a supporting bridge portion 6l having apertures 68 and 69 at the ends thereof adapted to be threaded by bolts 6l. It will be noted that apertures 68 and 69 are substantially larger than the diameter of each of the bolts and are so disposed as to be clear of the bolt.

From the center of the supporting portion 61 of the stationary contact member, an arm 19 extends upwardly and terminates in a contact supporting portion il upon which is mounted a stationary contact 12. The other corresponding contact is 72. A terminal lug 13 is provided for making connection to the stationary contact supporting member 67. Beyond each of the vstationary contact supporting members 65 and 66 are insulating sleeves 7 9 and l5 slidably mounted on bolt 6l, Beyond these sleeves M and l5 are crossbar members of metal 'i6 and ll extending across bolts 6l and forming a rigid bridge.

Nuts' 78 and 79 on the two bolts 6l hold the lentire stack rigid. Bridge members i6 and "il,

are provided with stii' upwardly extending massive portions and 8l normally registering with portion 'l0 of the movable contact of the stationary contact member El. Portions 8D and 8l are each provided with adjusting screws 82 and 83 having insulating tips 62 and 33 respectively. Screws 82 and 63 with their lock nuts 89 are adapted to bear heavily against arm portion 7U below stationary contact l2 and thus in effect to form a stiff spring mounting for the stationary contact.

It will be noted that the ends of core members 25 and 29 are offset from each other and that normally armature 99 is disposed between the two opposing pole faces. Frame has its side arms 96 and il disposed just beyond the bound-- aries of coils 35 and 36 and is adapted to operate in the space between these coils and the inside surface of the frame itself. Substantial latitude in the normal idle position of the armature between pole faces is permissible.

Windows i3 and lll in side arms il and l2 of the frame are normally adapted to register with the pole faces and armature 99 so that proper adjustment may be made.

Preferably the entire movable system is made of iron or steel and is highly magnetic. Since this movable portion of the system is directly carried by the upper portion of the frame it is clear that the armature 99 is coupled somewhat more closely to the upper magnetic circuit than it is to the lower magnetic circuit. In the normal operation of the vibrator both magnetizing coils 35 and 36 are simultaneously energized when the contacts are both open, and with armature i9 being disposed midway between the opposing pole faces, there will be a tendency for armature 99 to be attracted toward pole piece 29.

Itais understood of course that with the exception of the armature, the entire Vibratory portion may be made of non-magnetic metal. The

eiect of vthis will be to alter the coupling be-- ondary 95 mayfeed the stepped upalternating currents` to any suitable load here shown diagrammatically as a condenser 91 and resistance For proper starting, it is necessary to connect coils and 36 so that opposite poles will be produced at the pole faces. Due to magnetic eccentricity the armature becomes polarized and is pulled by one pole and pushed by the other toward one pole face. In some cases, it will be attracted toward the upper face and in other instances toward the lower, depending upon the properties and dimensions of materials. After starting, reversal of one coil will not generally result in stoppage. It is preferred to retain the coils in their original proper relationship.

The lack of magnetic symmetry at the start of vibrator operation results in the armature bey ing pulled in one direction. This unbalanced force is sufficient for starting purposes but appears to have no substantial effects on the operation thereof. It is believed that the unbalanced starting force is too small in comparison to the forces created during vibrator operation to have any substantial effect. Hence, after starting, the

vibrator appears to operate in a thoroughly symmetrical manner. 1

-Referring to the vibrating porti-on of the system shown in detail in Fig. 4, while springs 38 and 39 are shown as separate, it is evident that they may be 'integral with each other. It will therefore be apparent that when the expression a spring is used in the claims, it is to be understood as meaning a single spring as the result of combining springs 38 and 39 into one or duplicate separate springs as shown in Fig. 4.

It 'is to be understood that springs 58 and 59 may be replaced by one spring and this may be disposed anywherealong the rigid beam, due to the high degree of coupling furnished by the beam. The reeds 38 and 39 are the most flexible of the various springs. It is preferred to have springs 58 and 59 more flexible than the elastic mounting for the contacts. contact mounting, it is obvious that either the xed or the movable contact maybe mounted on a stiff spring, or both may be so mounted.

What is claimed is:

1. In a vibrator, a base, a pair of flat reeds rigidly mounted on one of the ends thereof on said base, a rigid elongated beam mounted on the other ends of said reeds, an armature carried by said beam at one end thereof and a movable contactmo'unted o'n the other end thereof,4

a stationary 'contact mounted on said base, at least one of said'mounting means having a higher resonant frequency than said reeds, a 'spring carried by said beam at the contact end and extending beyond the contact and being stiifer than said reeds, a weight carried by said spring, an electro-magnet mounted on said base, said electromagnet including a magnetizing coil and pole face in proximity to said amature, and contact and magnetizing coil connections for maintaining'said reed in vibration upon circuit energization.

2. The structure of claim 1 wherein the armature is mounted atone end of said beam with the reeds secured at an intermediate point of said beam.

3. In a vibrator, a base, -a pair of flat reeds rigidly mounted at one of the ends thereof on said base, a. rigid elongated beam mounted at the other ends of 'said reeds at an intermediate portion thereof, an armature 'carried by said With regard to thebeam at one end thereof and a movable contact on the other end thereof, a fixed contact on each side of said beam for alternate cooperation with said movable contacts, means for mounting said movable contacts on said beam, means for mounting said stationary contacts on said base, one of said mounting means having a higher resonant frequency than said reeds, a spring carried by said beam at the contact end and extending beyond the contact and being stiffer than said reeds, a weight carried by said spring, an electro-magnet mounted on said base, said electromagnet including a magnetizingcoil and a pole face in proximity to said armature, and contact and magnetizing coil connections for maintaining said reed in vibration upon circuit energization.

4. The structure of claim 3 wherein the mounting means for the stationary contacts have elasticity and wherein the movable contacts are rigidly mounted on said beam.

5. `In a vibrator, a base, a pair of flat reeds rigidly mounted at one of the ends thereof on said base, a rigid elongated beam mounted at the other ends of said reeds, an armature carried by said beam, movable contacts rigidly mounted on said beam, a fixed contact on each side of said beam for alternate cooperation with said movable conta-cts, means for mounting said fixed contacts on said base, said mounting means havingV a higher resonant frequency than said reeds, a spring stiffer than said reeds and a weight carried by said beam at the movable contact end thereof, an electro-magnet mounted on said base, said electro-magnet including a magnetizing coil and a pole face in proximity to said armature, and contact and magnetizing coil connections for maintaining said reed in vibration upon circuit energization.

6. The structure of claim 5 wherein the armature is mounted at one end of said beam with the reeds carrying said beam at an intermediate portion thereof.

7. In a vibrator, a base, a pair of flat reeds rigidly mounted at one of the ends thereof on said base, a rigid elongated beam mounted at the other ends of said reeds,- an Iarmature carried by said beam, movable contacts on said beam, a stationary contact on each side o f said beam for alternate cooperation with said movable contacts, means for mounting said movable contacts on said beam at an end thereof, means for mounting said stationary contacts on said base, one of said mounting means having a higher resonant frequency than said reeds, a spring stiffer than said reeds and a weight carried by said beam at the movable contact end, a pair of electro-magnets mounted on said base, each electro-magnet including a magnetizing coil andy a pole face, said pole faces being disposed opposite each other with the armature between them and adapted to vibrate back and forth between the opposed poleA faces, .and contact and magnetizing coilv connections for initiating and maintaining reed vibration, said connections providing opposite polarities for the opposed pole faces.

8. The structure of claim 7 wherein the armature is mounted at one end of the beam with the beam .carried by said reeds at an intermediate point thereof.

9. The structure of claim 7 wherein said beam is mounted on an intermediate portion thereof on said reeds with the armature at an end of said beam and wherein each of said magnetizing coils is shunted across a pair of cooperating contacts.

10. In a vibrator, a base, a pair of Iiat reeds rigidly mounted. at one of the ends thereof on said base, a rigid elongated beam mounted at the other ends of said reeds, an armature carriedV by said beam, movable contacts rigidly carriedi on said beam, a stationary contact at each side of said beam for alternate cooperation with said movable contact coil, means for mounting said stationary contacts on said base, said mounting means having a higher resonant frequency than said reeds, said movable contacts being mounted at an end of said beam, a spring stiier than said reeds and a weight carried by the Contact end of said beam, a pair of electro-magnets mounted on said base, each electro-magnet including a magnetizi coil and a pole face, with said pole faces being disposed opposite each other and the armature between them and adapted to l vibrate back and forth between the opposed pole faces, contact and magnetizing coil connections for initiating and maintaining reed vibrations, said connections providing opposite polarities for the opposed pole faces.

1l. The structure of claim 10 wherein said beam is carried on an intermediate portion thereon with the armature mounted at one end thereof.

12. In a vibrator, a base, a pair of reeds, means for mounting said reeds rigidly on said base in spaced parallel relationship, a rigid elongated beam carried by the other end of said reeds at an intermediate point of said member, an armature carried by one end of said beam, movable contacts carried by the other end of said beam, a

spring and weight carried by the contact end ofV said beam, stationary contacts carried by said base for alternate cooperation with said movable contacts, resilient means or'xnounting said stationary contacts on said base, said reeds being substantially less stiff than either said spring orv said resilient contact "mountings, at least one electro-magnet having a pole face in proximity toy said armature, and Contact and magnetizing coil connections for initiating and maintaining reed vibration.

13. The structure of claim 12 wherein a pair of electro-magnets are provided each having a pole face in opposed relation to the other with the armature therebetween.

i4. lin a vibrator, a U-shaped frame having a bight and sides, a pole piece extending from said bight up between said sides, a second pole piece supported on said frame and extending' toward the first, said pole pieces terminating in staggered faces, a magnetizing coil for each pole piece, a pair of reeds rigidly clamped at the ends thereof to said frame, a rigid beam carried by said reeds at their other ends, said beam emending down toward the bight and terminating in an' armature between the opposed pole faces,

movable contacts mounted on said beam, statonary contacts mounted on the free ends of said frame for cooperation with said movable contacts, and connections between said contacts and coils for vibrating said reed. y

mi? M. BRESSE-L. 

